I'm running about 38 dgs inital timing on this cam, numbers are at dur 50 thousand 252/262 lift 542/555 with 1.6 rockers. It's a 408 if that matters. Original booster had fluid in it so i bought a booster from Ramman.inc . Now i have 1 good push on brakes and that's it,they will almost lock up but let up and try and push again almost nothing... Been doing something research and i'm going to install a vacuum pump i believe... anybody got a better idea let me knowalso most solid cams have decent vacuum if they have enuf initial timing!